Solar cells using BaSi layers including Ba (barium) and Si (silicon) have been developed (Patent Literatures 1 and 2). BaSi has a wider bandgap than Si, and Sr (strontium) is added to a BaSi layer to obtain a bandgap of 1.4 eV, which is suitable for solar cells. In this manner, higher energy conversion efficiency can be achieved. To lower costs and obtain a smaller film thickness, a BaSi layer is preferably formed on an insulating substrate such as a glass substrate. As a method of forming a BaSi layer on a glass substrate, formation of (111)-oriented Si on a glass substrate is disclosed in Non-Patent Literature 1. Patent Literatures 1 and 2, and Non-Patent Literature 2 disclose techniques for forming a BaSi layer on (111)-oriented Si.
[Patent Literature]
Patent Literature 1: Japanese Laid-Open Patent Publication No. 2008-66719
Patent Literature 2: International Publication Pamphlet No. WO 2009/028560
[Non-Patent Literature]
Non-Patent Literature 1: J. Appl. Phys. Vol. 88, 124 (2000)
Non-Patent Literature 2: Jpn. J. Appl. Phys. Vol. 43, No. 4A, L478 (2004)